Piles made in the ground.
Such piles can easily be made exactly to the required length, after determining the real soil resistance determined during pile driving. This is their big advantage, as any errors arising from the preliminary land assessment can be corrected. This kind of adjustment cannot be made, in piles discussed previously.
Driven piles are made immediately on the construction site at the place of their destination, in the ground under the cover of a previously run-in casing pipe or without this cover in the hole made.
Casing tubes can be "recovered", i.e.. pulled out of the ground as piles are made. If piles are made in irrigated ground, and water is harmful to concrete, the cover remains permanently with the piles.
Covered or ground concrete is usually compacted by the use of tamping, vibrating or pneumatically. Non-compacted concrete piles are made less and less frequently.
The group of piles made in the ground can be included: pale Frankie, Strauss piles and Wolfsholz piles.
Pale Frankie. The execution of the Franki pile consists in driving a steel pipe with an internal diameter into the ground with a pile driver 400-600 mm, wall thickness 20-30 mm. A plug is made at the lower end of the pipe, enclosing the inside of the pipe, which prevents groundwater from entering the interior, and in addition, the driving of the pipe into the ground is performed by hitting the baby with the plug.
The period of execution of Franka piles is slightly longer than driving wooden or prefabricated piles, and the concrete piles have a high density, it is tight and resistant to the harmful effects of aggressive groundwater components.
There are vibrations during the construction of Franka piles and driven piles, which adversely affect neighboring buildings and equipment.
Pale wiercone. The group of bored piles includes Strauss piles and Wolfsholz piles. These piles are made this way, that the casing pipe is driven into the ground by a drilling method, i.e.. with simultaneous extraction of soil from inside the pipe, then it is gradually pulled up and concreted at the same time.
Strauss and Wolfsholz piles may be used at these locations, where the shock could have a bad effect on surrounding buildings or equipment. There are practically no shocks when made. Moreover, they can be performed under conditions, when the dimensions of the workplace are limited.
After making the Strauss pile hole to the designed depth, concrete is laid in it using containers with an opening bottom. Concrete portions of approx. 70 cm is tamped with a light rammer and the pipe is gradually pulled upwards, in such a way that there is always a concrete layer of at least a height in the pipe 30 cm.
Concreting of the Wolfsholz pile takes place after the water is displaced from the pipe by means of compressed air with lower pressure, concrete is supplied under slightly more pressure, and then high pressure air is admitted. Increased pressure compacts the concrete and presses it against the ground, which largely increases the load capacity of the piles.